Combined stretch and wipe forming machine with automatic traverse control of the wipe shoe



c. H. ROOT 3,096,806 COMBINED STRETCH AND WIPE FORMING MACHINE WITH AUTOMATIC TRAVERSE CONTROL OF THE WIPE SHOE Filed Aug. 17, 1960 2 Sheets-Sheet 1 July 9, 1963 IN VEN TOR.

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4 rrows/5W c. H. ROOT 3,096,806 COMBINED STRETCH AND WIPE FORMING MACHINE WITH AUTOMATIC TRAVERSE CONTROL OF THE WIPE SHOE July 9, 1963 2 Sheets-Sheet 2 Filed Aug. 17, 1960 251 f? I OLA m. a two. 5/

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30 DlREc'noN 0F ABLE ROTATION United States Patent 3,096,806 COMBINED STRETCH AND WIPE FORMING MA- CHINE WITH AUTOMATIC TRAVERSE CON- TROL OF THE WIPE SHOE Clinton H. Root, Maple Heights, Ohio, assignor to The (iyril Bath Company, Solon, Ohio, a corporation of Ohio Filed Aug. 17, 1960, Ser. No. 50,280 9 Claims. (Cl. 15340) This invention relates to a combined stretch forming and wipe forming machine employing a traversing wipe shoein which the traversed positions of the wipe shoe are automatically controlled in relation to the wrapping of the stock onto the side face of the die.

More specifically, the invention relates to a wipe shoe and control. combination by which the wipe shoe is automatically maintained in the most effective wiping position in relation to that normal instantaneous line of' tangency of the stockcand die which would result from the applied stretch forming tension in the absence of any wiping operation.

The present invention is an improvement on the combined wipe and stretch forming machine disclosed in the Dolney and Hein patent, No. 2,810,421, issued October 22, 1957, the improvement residing principally in the control for controlling the traversing of the wipe shoe and the manner of incorporation of some of the control components in the wipe shoe.

In the combined wipe and stretch forming of stock onto aside face die, it has been found desirable to main tain the common. line of contact between the wipe forming face of the shoe, the stock, and the side face of the die near to the normal instantaneous line of tan-gency of the stock and die at all times. This normal instantaneous line of tangency is that resulting from the tensioning of. the stock by the. stretch forming assemblage in the absence of any wiping operation.

In the use of circular dies concentric with the turntable; this normal line of tangency remains in fixed position relative to the line of thrust of the wipe forming shoe while the shoe is held fixedly in non-traversing position.

However, in cases wherein the radius of the curvilinear ontlineof the die varies, or the axis of a circular die is offset from the table axis, the normal instantaneous point of tangency shiftsor mignates endwise of the stock from such-line of thrust as the table is rotated. Sometimes the migration is quite rapid and extensive. This is true particularly when the stock passes from a relatively sharply curved. portion of the die face onto a face portion that is relatively flat or only slightly curved.

Since the position of the normal instantaneous line of tangency migrates rapidly in such cases, it is necessary totraverse the wipe shoe generally lengthwise of the side face of the die, in a direction generally toward the stretch forming. assembly so as to maintain the line of contact of the shoe with the stock at or close to the normal instantaneous line of tangen'cy.

It is desired in some operations that the line of contaot of the wipe shoe with the stock and die lead or lag the normal instantaneous point of tangency to a limited extent, so as to slightly understress or overstress the stock, or to cause other specialized effects. This lead or lag generally is not great, and can be deliberately introduced and controlled, as desired.

Hereinafter, the normal instantaneous line of tangency designates that line oftan-gency of the stock and die that occursat a given instant in the absence of the application. of the wipe forming shoe to the stock and while the stock is being applied to the 'die face solely by rotation. of the table and under stretch forming ten- 3,095,806 Patented July 9, 1963 sion applied by the stretch forming assemblage. Likewise, the predetermined instantaneous line of contact of the wipe forming shoe and stock hereinafter designates a line of contact superposed on such normal instantaneous line of tangency, or within predetermined controlled maximum limits thereof, either forwardly or rearwardly therefrom in the direction of travel of the stock.

A principal object of the invention is to provide a control for controlling the power drive of the traversing shoe so as to maintain the shoe at the perdeterrnin'ed instantaneous point of contact of the stock on the die.

A more specific object is to accomplish this result by a very simple and effective control having few moving parts whichare generally simple, relatively inexpensive, and readily available.

Another object is to provide a wipe shoe and sensing combination for sensing the relative approach and recession of either the face of the stock, or the side face of the die, relative to the shoe in the direction of the line of application of the wiping pressure at locations which are spaced endwise of the stock from the portion of the shoe which is in pressure wiping contact with the stock.

Other objects and advantages will become apparent from the following description wherein reference is made to the drawings, in which:

FIG. 1 is a diagrammatic top plan view of the combined wipe and stretch forming machine embodying the principles of the present invention;

FIG. 2 is a wiring diagram showing the control for the traversing of the wipe shoe;

FIG. 3 is an enlarged fragmentary side elevation of a part of the machine illustrated in FIG. 1 and showing the wipe forming shoe, its support, and the sensing devices used in connection therewith;

FIG. 4 is a top plan View of the structure illustrated in FIG. 3;

FIG. 5 is a view similar to FIG. 3, partly in vertical section, illustrating the shoe with a modified form of the sensing device;

FIG. 6 is a top plan view of the structure illustrated in FIG. 5;

FIG. 7 is a fragmentary top plan view of the shoe illustrating another modification of the sensing device used in connection with the present invention; and

FIG. 8 is a diagrammatic top plan view of the die and shoe showing the cooperation of the sensing devices and stock in different positions of the shoe along the stock and relative to the die face.

Referring first to FIG. '1, the machine shown by way of illustration is that disclosed in the Dolney and Hein patent, No. 2,810,431, issued October 22, 1957, the operation thereof, aside from the control of the traversing of the shoe and the shoe and its sensing devices, being apparent from the patent.

Briefly, the machine comprises a frame 1 on which is rotatably mounted a turntable 2 which may be driven by means of a ring gear 3 and pinion gear 4. The pin-ion gear is driven by a hydraulic motor 5 to which fluid pressure is supplied by a pump 6 driven by an electric motor 7. The conventional controls can be used for controlling the speed and direction of rotation of the table.

Mounted on the frame 1 in spaced relation to the table is a support 8 which is rotatable or oscillatable about an upright pedestal 9 and which, in turn, supports a stretch forming piston and cylinder assemblage 10 com prising a piston 11 and a cylinder 12. The assemblage is reversible and operating pressure fluid is supplied thereto through a suitable reversing valve 13 to which pressure fluid is supplied by a pump 14 driven by a motor 15.

Mounted on the support 8 for movement endwise thereof is a suitable slide 16 which is connected to the rod 17 ofthe piston. The slide 16 carries a stretch forming grip head 18 which is connected to one end of the stock member 19 which is to be formed about the side face of the die.

A side face die 25 is mounted on the table 2 for rotation therewith and has a curvilinear side'face. A clamp 26 is secured on the die or table for rotation in fixed position relative to the die and is in clamping engagement with the opposite end of the stock member 19 and connects it for rotation with the die. Thus, by driving the table in the direction indicated by the arrow in FIG. 1, with tone end of the stock member 19 clamped at 26 and the other end clamped by the gripping head 18, the stock member 19 is stretch formed about the side face of the die 25 progressively as the table rotates.

For combined wipe and stretch forming, a traversing wipe forming mechanism is provided. This mechanism comprises a wipe shoe 30 mounted on a pedestal 31 of a slide 32 which is slidable in suitable guideways 33 toward and away from the side face of the die. The guides are mounted on a traversing carriage 34.

Also mounted on the carriage 34 is a reversible wipe forming piston and cylinder assemblage 35, including a cylinder 36 and a piston 37 having a rod 38. The rod 38 is connected to the pedestal 31 for applying the wipe forming pressure to the shoe. Pressure fluid is supplied to the assemblage 35 through a suitable reversing valve 39 to which fluid pressure is supplied, in turn, by a pump 40 driven by a motor 41.

The traversing carriage 34, in turn, is mounted on a guideway 45 extending generally endwise of the length of stock. In the form illustrated, the guideway 45 is lineal.

In order to traverse the carriage 34, power means in the form of fluid pressure operated reversible piston and cylinder assemblage 46 are provided. This assemblage includes a cylinder 47 and a piston 48 having a rod 49 which is connected to the carriage 34. Pressure fluid for operating the assemblage 46 is supplied through a suitable reversing valve 56 which is operated, in turn, by solenoids 51 and 52. The pressure fluid is supplied to the valve 50 by a pump 53 driven by a suitable motor 54.

By selective operation of the solenoids 51 and 52, the valve 50 can be operated to cause the traversing carriage, and thereby the shoe 30, to move forwardly and rearwardly alongside the side face of the die. When the table is rotating as illustrated in FIG. 1, the forward direction is opposite to the direction of rotation of the table and the reverse or rear direction is the same as the rotation of the table.

The structure thus far described is of the general type shown in the above Dolney and Hein patent. However, as mentioned hereinbefore, it is desirable that the contact surface portion of the wipe shoe 30' be maintained normally at the predetermined instantaneous line of contact of the stock member and the side face of the die during rotation of the table.

In order to maintain the shoe in the proper position along the die face so that this line of contact does not exceed a predetermined maxi-mum distance in advance or to the rear of the normal instantaneous line of tangency, the wipe shoe is provided with suitable sensing devices to which a control of the valve 50 of the assemblage 46 is responsive. As best illustrated in FIG. 4, the wipe shoe has a contact portion, indicated at 6%), which generally is near the center of the shoe in a direction endwise of the stock and side face of the die. The forwardface of the shoe generally is lineal in a direction endwise of the stock. As a result, when the central or contact portion 60 is in the position in which it normally engages the stock and presses it against the die, the face portions of the shoe near its ends are spaced from the face of the stock 19.

The shoe preferably is in the form of a rigid metal frame 61 in which is carried, in fixed position, a suitable wiping block 62 of nylon or other suitable material. The block 62 is arranged so that its forward face, with the portion 60 thereon, is exposed in position to engage the side face of the die. Carried by the block 62 are two sensing devices which, in the form illustrated in FIGS. 1 through 3, are metallic electrical contact pins 63 and 64. These contact pins are spaced at opposite ends, in the direction lengthwise of the stock, of the portion 60. The forward faces of the pins 63 and 64 may be flush with the forward face of the block 62, or may extend a slight distance forwardly therefrom. Generally, when the shoe is applied to the stock to press the stock against the die, the face portion 60 of the shoe is tangent to the die face and the stock curves away from the contact portion 60 of the shoe both forwardly and rearwardly in the direction of wiping along the stock. The pins 63 and 64 are inactive to perform any function when not engaged with the stock 19.

In the form illustrated, they are connected to, and form part of, suitable control means. The control means comprises a pair of relays, indicated at 68 and 69, respective-ly, as shown in FIG. 1. As illustrated in FIG. 2, the relay 68 has a pair of normally open contacts 68:: and 68b and a normally closed contact 630. The relay 69 has a pair of normally open contacts 69a and 69b and normally closed contact 69c. In order to energize and deener-gize the relays 68 and 69, one terminal of each of the relays is connected to one line 70 of a 12-volt circuit energized by a transformer 71. The other line 72 of the lZ-Volt circuit is connected to ground. The other terminal of the relay 68 is connected to the contact 63. The terminal relay 69 is connected to the contact 64.

Usually, the side face die is metal and, of course, the stock to be formed is metal. Consequently, the die or the stock also is connected to ground. This may be done by connecting the die to ground, or by connecting some part of the piston and cylinder assemblage 10, or the grip head 18, or the stock 19 itself, to ground.

Generally, the contacts 63 and 64 are arranged to engage and disengage the stock itself, but, if desired, they may be arranged to engage and disengage a portion of the side face, for example at one edge of the stock, as the shape of the die face to a large extent dictates and controls the position of the tensioned stock. However, the best result is obtained by engaging the stock itself with the contacts, as the engaged location on the stock at the forward end of the shoe in the direction lengthwise 0f the side face sometimes is not in contact with the face of the die.

' With the wipe shoe in the position illustrated in FIG. 1, neither of the contacts 63 or 64 engages the stock. Therefore, the two relays are unenergized. However, should an elongated portion of the side face of the die having much less curvature, as indicated at X in FIG. I, approach the predetermined instantaneous line of contact of the wipe forming shoe with the stock, the stock would be moved toward the shoe in the direction of applied wiping pressure and eventually engage the contact 63. Upon the making of contact between the contact 63 and the stock, the relay 68 is energized by the electrical signal resulting from closing the circuit. This energization operates the relay 63 so as to cause it to operate the valve '50 so that the valve, in turn, causes the traversing assemblage 56 to move the carrier 34, and thereby the shoe 30, in the forward direction, this being the direction opposite to the direction of rotation of the table. The shoe continues traversing forwardly until it reaches a location at which the contact 63 breaks contact with the stock, at which location the wiping surface of the shoe is at the instantaneous line of contact. If the flattened portion X is of great enough extent and sufficiently fiat, the contact 64 also will be brought into contact with the stock. Thus both the relays 69 and 68 will be energized concurrently. As will later be explained, the circuit is such that, when both relays 68 and 69 are energized, the valve 50 will be operated to cause the assemblage 46 to continue moving the table 34 in the forward direction.

Again, this forward direction of movement continues until the contact 63 leaves the stock, in which case only the contact 64 remains in contact. When the contact 63 leaves the stock, the relay '68 is deenergized but the relay 69 remains energized. Energization of the relay 69 alone, however, causes the valve 50 to be set to operate the piston and cylinder assemblage 46 to reverse traversing direction of the carriage 34- and shoe 30; This reversal continues until either the contact 64 leaves the stock and breaks con-tact therewith, or until the contact 63 again engages the stock. In the former case, the reverse traverse of the shoe temporarily ceases. In the latter case, it ceases in the reverse direction and immediately begins in the forward direction.

Different degrees of sensitivity and different maximum limits can be established by preselecting the position of the contacts 63 and 64 with respect to each other and the distance of each forwardly and rearwardly, lengthwise of the side face, from the contact portion 60. It is to be understood that the contacts do not have to be equidistant from this portion.

Referring next to FIG. 2, the wiring diagram is shown indicating the coaction of the contacts of the relays with the solenoids 51 and 52 for operating the valve 50 to provide the traverse operations described. The solenoid 51 is operative when energized to cause traversing of the shoe in the forward direction, which is opposite to the direction of rotation of the table. The solenoid 52 is operative when energized to cause traversing of the wipe shoe in a reverse direction, which is in the direction of rotation of the table. For this purpose, the solenoid 51 has one terminal connected to line L to a suitable 110- volt source. The opposite terminal of the solenoid '51 is connected to the line L of the opposite side of the 110- volt source. The normally open contact 68b and the normally closed contact 69c are connected in the series between the solenoid 51 and the line L The solenoid 52 has one terminal connected to the line L and the opposite terminal connected to line L with the normally closed con-tact 68c and the normally open contact 6% interposed, in series with each other, between the latter terminal and the line L A bypass circuit is arranged in bypassing relation to the contacts 68b and 690. This bypass circuit is connected at one end to the latter terminal of the solenoid 51 ata location between the latter terminal and the contacts 68b and 690. The other terminal of the bypass circuit is connected to the line L Interposed in the bypass circuit in series with each other are the normally open contact 68a and the normally open contact 69a.

The operations above described are obtained with the circuit described. For example, when the contacts 63 and 64 are out of contact with the stock, no power is supplied to either relay, due to the normally open contacts 69b, 68b and 68a and 69a. When contact 63 makes contact with the stock energizing the relay 68, the normally closed contact 680 opens so that no power can reach the solenoid 52. Likewise, the normally open contacts 68a and 68b close, and the solenoid 51 is energized through the normally closed contact 69c and the now closed contact 68b. Further, a standby circuit is partially established through the now closed normally open contact 63a. With the solenoid 51 thus energized, the shoe traverses forwardly opposite to the direction of rotation of the table until the contact 63 again breaks contact. During this traverse, the contact 64 engages the stock and thereby energizes the relay 69 so that both relays are in energized condition concurrently. This closes contactwb, but, on the other hand, opens contact 68c so that the relay 52 is not energized. Further, while it closes contact 68b, it opens contact 690, so that the solenoid 51 cannot be energized through its normal circuit. However, it closes contacts 68a and 69a in the bypass circuit so that the solenoid 51 is energized through the bypass cir- 6 cuit and hence the shoe continues tomove forwardly until the contact is broken between the contact 63 to stop the forward traversing movement. The contact 64 -is still in contact with the stock. Hence, only the relay 69 is energized. In this condition, normally closedcontact 680 remains closed and the normally open contact-69b is closed, thus energizing the solenoid-'52. As aresult", the solenoid 52 operates the valve 50 so as to cause the table, and thereby the shoe 30, to be traversed in the reverse direction or inthe direction of table travel. Such reverse traverse continues while only the contact 64* is still in contact, but it eventually causes contact 63 to re= turn into contact. If both contacts 63 and 64' are out of contact, the shoe stops. If bot-h are brought into contact, the shoe immediately starts again and traverses in the forward direction. If only contact 64 is' in contact; the shoe traverses rearwardly.

Thus, the shoe hunts and finds itself in the proper predetermined instantaneous contact position at all times.

The sensing devices thus provided, and the control means associated therewith, are relatively simple and compact and noteasily damaged. However, other controls may be used. For instance, as illustrated in FIGS. 5 and 6, a shoe Si) is illustrated which is the same as the shoe 3t} heretofore described, except for the sensing devices themselves. In this form, the shoe includes a suitable nylon or insulating block '81 in which are mounted pressure transmitting pins 82. Mounted on' the shoe are two micro-switches 83 and 84 which are of the self-restori ng type. Thrust transmitted by the pins 82 need be very slight to operate the switches, and hence the pins may be mounted for sliding movement in the block' 81, or may be bonded thereto and moved due to elastic deformation of the block. These pins operate the microswitches to make contact when pressure is applied to them, so that the micro-switches operate essentially in the same manner as the contacts 63 and 64 and' are similarly connected in the circuit. Obviously, the circuit may be a two-wire circuit rather than a. grounded circuit, if desired.

Again, as illustrated in FIG. 7, instead of microswitches, the sensing means may be switches in the form of strain gauges. As illustrated in FIG. 7, the'shoe includes a block 9 1 to which are aflixed' strain gauges 92 and 93. These gauges, as is disclosed in the U.S. Patent No. 2,849,048, issued August 26, -8, respond to the elastic deformation of the block'90 at their locations and produce an electrical signal in response to that deformation. These signals are used in the same manner as the signals from the contacts 63 and 64, or switches *83 and 84, heretofore described, but, if course, an amplifier is required in the circuit to amplify the signal current supplied by the patches before delivering it to the relays. The contacts illustrated in FIGS. 1 through'3 are preferred so that the shoe can operate on only a light feather touch.

The shoe can be of the sliding or rolling type and, if of the rolling type, the sensing means, are. positioned on the shoe forwardly or rearwardly of the roll..

Referring to FIG. 8, a die D, having a side face with shanp and flat curves, is illustrated and the shoe 30 is shown in different wiping positions. therealong. I'n p0 sition A, neither contact 63 or 64 is engaging the stock, so the shoe remains in a fixed traversed position. As the die swings to the right so that the shoe is at position B, contact 63 makes contact. Immediately, the shoe traverses to the left, contact 63 remaining in contact. When it reaches position C, both contacts .63 and 64 are in contact and left or forward travel continues.v When it. reaches position D, contact 63 has broken contact but contact 64 remains in contact. The shoe has over-run slightly. Thereupon, due to contact 64, the shoe traverses to the right until contact 63 is again in contact, wheneupon the shoe starts forward again. Thus, the shoe hunts and maintains its proper position. There is inherently a slight time delay in operation of the assemblage 46, so that the hunting is not a rapid to and fro weaving but almost a constant forward movement with occasional slight hesitation or reverse movement.

It is apparent, therefore, from the foregoing description, that during the combined wipe and stretch forming operation, the traversing wipe shoe is controlled automatically so as to maintain its preselected point of contact with the stock at all times within the limits selected relative to the normal instantaneous line of tangency of the stock and the die which would result were the wipe shoe not in contact. Thus, the Wiping is effected at the preferred location.

Furthermore, the traversing can be so controlled that a slight overstressin'g or understressing can be obtained, if required, by causing the sensing means to apply the shoe in a leading or lagging relation to the normal instantaneous line of tangency.

Having thus described my invention, I claim:

1. In a stretch forming machine, a power driven rotatable table, a side face die member thereon and having a curvilinear side face, means for connecting one end of an elongated stock member for rotation with the die, power driven stretch forming means adapted for connection to the other end of the stock member for applying yieldable tension thereto endwise thereof as the stock member is wrapped on the die member by rotation of the table for stretch wrapping the stock onto the die face, a traversing wipe shoe, power driven wipe forming means for yieldably urging the shoe against the stock member on said side face, traversing power means operable for traversing the shoe in opposite directions, selectively, endwise of said side face independently of rotation of the table, said shoe having a normal contact portion to be pressed against the stock member and thereby press the stock member against the side face normally at that instantaneous line of tangency of the stock member and side face of the die resulting from the stretch wrapping during rotation of the table, sensing means carried by the shoe and including a pair of sensing devices on the shoe and spaced from each other endwise of the wiping path at opposite sides of said normal contact portion, and operative, when both devices are spaced a predetermined distance from the surface of one of the members, to give a non-traverse signal, and while one of the devices nearest said other end of the stock and said surface approach each other to a predetermined extent while the other device remains a predetermined distance from said surface to give a forward traverse signal, and when said surface and both devices approach each other to a predetermined extent to continue the forward traverse signal, and when said surface and said one of said devices recede from each other to a predetermined extent while said other device remains in an approached position relative to said surface, to give a reverse traverse signal, and control means connected to the signal means for receiving said signals and operatively connected to the traversing power means, and operative in the response to the non-traverse signal, to cause the traversing power means to lock against traversing, and operative in response to the forward traverse signal to cause the traversing power means to traverse the shoe toward said other end of the stock, and operative in response to the reverse traverse signal to cause the traversing power means to traverse the shoe toward said one end of the stock.

2. A machine according to claim 1 wherein said normal contact portion, in response to the signal means, seeks a location adjacent the location of the instantaneous line of tangency of which the stock member would have relative to the die under the pull of the stretch forming means were the wipe shoe unapplied to the stock member at the particular instant during stretch forming.

3. A machine according to claim 1 wherein the devices are electric switches.

4. A machine according to claim 1 wherein the devices are adapted to be operated by contact with the surface of the stock member.

5. A machine according to claim 1 wherein the devices are switch devices having electrical contacts with portions disposed for direct electrical contact with, and dis engagement from, the stock member, circuit means connect the contacts electrically with the control means, and the stock member is a conductor portion of the circuit means.

6. A machine according to claim 1 wherein the devices are strain gauges on the shoe at spaced locations endwise thereof and are rendered operative by elastic deformation of the shoe at said locations, respectively.

7. In a stretch forming machine, a power driven rotatable table, a side face die thereon and having a curvilinear side face, means for connecting one end of an elongated stock for rotation with the die, power driven stretch forming means adapted for connection to the other end of the stock for applying yieldable tension thereto endwise thereof as the stock is wrapped on the die by rotation of the table for stretch wrapping the stock onto the die face, a traversing Wipe shoe, power driven wipe forming means for yieldably urging the shoe against the stock on said side face, traversing power means operable for traversing the shoe in opposite directions, selectively, endwise of said side face independently of rotation of the table, said shoe having a normal contact portion to be pressed against the stock and thereby press the stock against the side face normally at that instantaneous line of tangency of the stock and side face of the die resulting from the stretch wrapping during rotation of the table, sensing means for sensing deviation of said portions of the shoe from said instantaneous line of tangency and including sensing devices spaced apart from each other endwise of the wiping path at opposite ends of said normal contact portion, said devices being operatively connected to portions of the stock at opposite sides of said instantaneous line of tangency, respectively, and each device being rendered operative in response to positions of its associated stock portion in the direction of thrust of the wipe shoe for producing control signals, and operating means responsive to the control signals to cause the traversing power means to traverse the shoe in the direction for positioning said normal contact portion at the instantaneous point of tangency.

8. The structure according to claim 7 wherein the devices are electric switch means respectively and each device is operable to close a circuit to the operating means in response to predetermined positions of its associated stock portion relative to the associated device in said direction of thrust.

9. The structure according to claim 7 wherein the stock forms a part of an electric control signal circuit, each device has an electrical contact portion engageable with, and disengageable from, its associated stock portion, depending on said position of its stock portion in said direction of thrust, and said control signals of each device are due to the making and the breaking of the circuit, respectively, by their associated electrical contact.

References Cited in the file of this patent UNITED STATES PATENTS 2,342,745 Maize Feb. 29, 1944 2,810,421 Dolney et al Oct. 22, 1957 2,988,127 Gray a June 13, 1961 3,062,266 Abbott Nov. 6, 1962 

7. IN A STRETCH FORMING MACHINE, A POWER DRIVEN ROTATABLE TABLE, A SIDE FACE DIE THEREON AND HAVING A CURVILINEAR SIDE FACE, MEANS FOR CONNECTING ONE END OF AN ELONGATED STOCK FOR ROTATION WITH THE DIE, POWER DRIVEN STRETCH FORMING MEANS ADAPTED FOR CONNECTION TO THE OTHER END OF THE STOCK FOR APPLYING YIELDABLE TENSION THERETO ENDWISE THEREOF AS THE STOCK IS WRAPPED ON THE DIE BY ROTATION OF THE TABLE FOR STRETCH WRAPPING THE STOCK ONTO THE DIE FACE, A TRAVERSING WIPE SHOE, POWER DRIVEN WIPE FORMING MEANS FOR YIELDABLY URGING THE SHOE AGAINST THE STOCK OF SAID SIDE FACE, TRAVERSING POWER MEANS OPERABLE FOR TRAVERSING THE SHOE IN OPPOSITE DIRECTIONS, SELECTIVELY, ENDWISE OF SAID SIDE FACE INDEPENDENTLY OF ROTATION OF THE TABLE, SAID SHOE HAVING A NORMAL CONTACT PORTION TO BE PRESSED AGAINST THE STOCK AND THEREBY PRESS THE STOCK AGAINST THE SIDE FACE NORMALLY AT THAT INSTANTANEOUS LINE OF TANGENCY OF THE STOCK AND SIDE FACE OF THE DIE RESULTING FROM THE STRETCH WRAPPING DURING ROTATION OF THE TABLE, SENSING MEANS FOR SENSING DEVIATION OF SAID PORTIONS OF THE SHOE FROM SAID INSTANTANEOUS LINE OF TANGENCY AND INCLUDING SENSING DEVICES SPACED APART FROM EACH OTHER ENDWISE OF THE WIPING PATH AT OPPOSITE ENDS OF SAID NORMAL CONTACT PORTION, SAID DEVICES BEING OPERATIVELY CONNECTED TO PORTIONS OF THE STOCK AT OPPOSITE SIDES OF SAID INSTANTANEOUS LINE OF TANGENCY RESPECTIVELY AND EACH DEVICE BEING RENDERED OPERATIVE IN RESPONSE TO POSITIONS OF ITS ASSOCIATED STOCK PORTION IN THE DIRECTION OF THRUST OF THE WIPE SHOE FOR PRODUCING CONTROL SIGNALS, AND OPERATING MEANS RESPONSIVE TO THE CONTROL SIGNALS TO CAUSE THE TRAVERSING POWER MEANS TO TRAVERSE THE SHOE IN THE DIRECTION FOR POSITIONING SAID NORMAL CONTACT PORTION AT THE INSTANTANEOUS POINT OF TANGENCY. 